Telephone receiver



W. W. DEAN.

TELEPHONE RECEIVER.

APPLICATION FiLED MAY 10, 1916.

Patented Aug. 24, 1920.

2 SHEETS-SHEET 1.

W. W. DEAN.

TELEPHONE RECEIVER. APPLICATION FILED MAYIO, 1916.

1,350, 594:. Patented Aug. 24, 1920.

I 2 SHEETS SHEET 2. 5% 5 Ema Liar V UZi YI JIU 1H llan UNITED S ATE -PATENT oF-Fic-E} WIIILIAM'W. DEAN, OF'RQCHESTER, New YORK, ASSIGNOR T STROMBERG-CARLSON TELEPHONE MANUFACTURINGCOMPANY, A CORPORATION or NEW YORK.

i TELEPiiQNE-REGEIVER.

Specification of Letters Patent. Patented Aug. 24', 1920.

Q A licant-amenit 1c, 1916. sriaino. 96,469.

To all whom it mag) concern:

Be it known that l, WILLI M Dean,

' a citizen of the United States, residing at ceivers.

Rochester, in the county of Monroe and State of New York, have invented a certain new and useful Improvement in Telephone- I accompanying drawings, an embodiment of my invention in a direct current receiver;

Figure 1 is a dissected View of a complete direct current receiver; 7

Fig. 2 is a longitudinal cross section showing the cup, the electro-rnagnet and the terminal block in section;

Fig. 8 is a rear end elevationfof the electro-magnet; i Q V A Fig. 4:" is a side elevation of the electromagnet; I

Fig. 5 is a perspective view ofthe terminal block withjthe terminals mounted thereupon; i

Fig. 6 is "a front elevation otf'the cup and the electro-magnet showing the wrench for unscrewing the cup from the shell;

Fig. 7 is a rear elevation-otthe cup showing the manner of applying the wrench to tree the cup from the receiver cap.

The direct current receiver, as illustrated comprises the cap 1 and the shell,

in Fig. 1, v 2 which form the casing of theoperating parts inclosed within them. The operating parts comprise the diaphragm 3 and the electro-magnete which electrmmagnet is mounted in the cup The cup 5' is provided with -a rear threaded portion and a front threaded portion 7 which cooperate with suitable threads in the shell-f2 and the cap '1 respectively. The cap 1 holds the diaphragm 3 firmly upon the seat 8 which is formed upon tlietront edge of the "cup.

To this' end the capl is provided with a narrow annular ring 9 which, when the cap is screwed in place, lies centrally of the wide seat 8 upon the front of the cup so ,as

to hold the diaphragm 3 as nearly as pos-v sible in a plane without strain or tension.

Inasmuch as the cap 1 and shell 2 screw upon the cup portion 5, it is obvious that whenit is attempted to remove the cap and shell, one or the other will first unscrew and be thus removable. In the event thatlthe cap 1 screws oft first, a very poor hold is afforded on the threaded portion7 for unscrewing the shell 2'from the threaded portionf6, and vice versa in case the shell 2' unscrews first a very poor and ineffective hold is' afl'orded by thethreaded portion 6. To overcomethis difiiculty Tprovide perforations 'at lQ and 11. A double ended spanner wrench 13 having a pin 14 adapted to pass into the hole 10 and a pin 15 adapted to engage 'the hole 11 is provided to remedy the aforesaid difliculty. V

The cup 5 is formed of a brass stamping to have a tapered portion 16, a recurved rim portion 17 and a cylindrical portion 18 for receiving the electro-magnete. The bottom 19 of the cup is flat to fit the square end of the electro-magnet 41' as can be seen in Fig. 2. i

The bottom of the cup is perforated at the center to receive the flat headed screw bolt 20 which passes loosely through the block of insulation 21 andis threaded into the lug or ear 22. A pair of smaller perforations 23+23 are made in the bottom of the cup adjacent the outer edge thereof. A pair of metallic terminals 2 1'24 are mounted upon the block of insulation 21 and secured thereto by means of the small vflatfheaded screws 25. These terminal pieces 24 areprovided with narrow stamped up from the sheet metal in a con extensions 26 which are tinuous piece with the parts 24;. .The pins .26 project through the perforations '23 in mentto the pins of the terminals of thecoil 27"of the, electro-magnet 4. The terminal pins'26 are covered with sleeves of insulate by means of screws and brass clamping ing material 28, as shown in Fig. 2, to preclips 30, as can be seen from Figs. 1, 5' and 7, comprise a fiat portion 31 which, when the clip is in place, lies upon the face of the terminal stamping 24. A grooved portion 32 has an overhanging lip 33 which lies against the side of the stamping 2t and the block 21, as may be seen in Fig. 7, to prevent the terminal clip from rotating with respect to the terminal stamping 24. The terminal clip 30 forms a universal clip since it is adapted to receive the round end of the wire within the grooved portion 32 'orto receive a terminal pin therein, or to receive a fiat terminal clip such as is 'illustratedin Fig. 1 on the tip of the receiver cord, either beneath the clip 30 or beneath the screw 29, as the casemay be.

The eleetromagnet 4 comprises aseries of The E-shaped stam'pings of silicon steel. bases of these stampings are held together blocks 35 into which the screws are threaded. The dim'ens1ons of the blocks 35 are such that when the same are clamped in place upon the ends of the jstampings '36, the di ameter of the'compound structure will be such as to fit snugly into the cylmdricalboa tom portion of the cup 5. pair of screws 37 pass through suitable openings in the bot-' tom of the cup 5 and are threaded into holes 38 in the brass blocks 35 thereby holding the magnet structure firmly in posltion 1n the bottom of thecup. The brass blocks 35 are similar so that only one part need be carried in stock, It will be noted that one of. the s rews 34- threads into the upper blockand one into the lower block. g A spool 39 of insulating material, preferably of 'balrelite v or of bakelized fiber" is forced upon the middle limb of the magnet structure and serves to support the coil 2?. The end of the magnet structure and the end of the spool 39 are ground off so as to maintain a predetermined distance between the diaphragm3 which seats upon the edge of the shell and the face of the electro1nag not. ll'have found that a relatively small number of turns of low resistance wire will give in this structure very good results. 1 have employed in practice a coil of 300 turns having 5 ohms resistance with highly satisfactory results under severe commercial conditions. While the above proportions have been found well suited for certain purposes where a low resistance is the prime requisite, I do notdesire to limit my invention to such proportions but find that the improved construction lnvolvlng the use of."

. labor.

wound on a smaller core. For instance, re-

ceivers have been constructed usin 1,250

' turns of wire which has a resistance or about 35 ohms and which receivers use only half the amount of silicon steelas the low-resistance receivers immediately above mentioned.

The receiver which I have described is adapted for rapid assembly under factory conditions. To this end the parts are built up as unit structures which may be readily assembled in'fi'nal form with a minimum of The electro-magnet structure :1 is built up as a unit, the terminal block portion is grouped as a unit and is then secured to the cup after which the magnet structure is secured to the cup, the terminals of the electro-magnet are soldered to the terminal pins of the terminal block, the receiver-cord is then attached and the casing and ear cap screwed in place with the diaphragm in front of the magnet. It is to be noted that the receiver cord has an extension 40 of the jacket'thereof which is connected to the lug 22 to relieve the cord of strain.

I have found that the characteristics of silicon steel are peculiarly valuable in direct current receivers, as compared with the best Swedish iron or mild steel heretofore employed. I find that silicon steel has a magnetization curve which rises sharply 'for relatively low values ofcurrent strength as compared with the best material heretofore used. For greater values of current strength the curve flattens out to a greater degree than with the best 'materialheretofore used and finally the steel becomes saturated at a relatively much lower point than prevalls 1n the best material heretofore.

used.

The result of these features permits the receiver of my'invention to operate according to a law of action entirely different from that of prior receivers. I am able to use the receiver successfully on longer lines than has heretofore been possible because it will operate satisfactorily on less current than the best receivers of the prior art. I can use the receiver successfully on heavier current flow than any receiver of the prior art under similar conditions. The characteristics of the steel permit the proper magnetization to be secured with a less number of turns on the magnet and a consequently lower induction. 'This permits a truer and longer transmission than any receiver heretofore known. provides such advantageous featuresthat it makes possible a wholly different operation of a telephone system and greatly increases And' finally this receiver ard 24 volt battery the usual prior art receiver on a short line will receive so much current that the diaphragm will .be drawn completely against the core of the magnet and rendered useless. On a long line such a receiver will not be suiliciently magnetized to transmit speech.

heretofore feasible.

, What I claim is:

1. In a directcurrent receiver, a normally non-polarized telephone receiver core of magneticmaterial, having the characteristic of silicon steel,namely, high magnetization on low current strength and having a relatively flat magnetization curve for higher current strength as compared with Swedish iron.

2. In a directcurrentreceiver, a normally nonpolarized telephone receiver core of magnetic material, having the characteristic of silicon steel, namely, high magnetization on low current strength, and-relatively low magnetization on higher current strength as compared with Swedish iron.

8. In a direct current receiver, a normally nonpolarized telephone receiver core of magnetic material, having the following characteristics, a sharply rising flux curve on lowcurrent strengths and a relatively flat flux curve on higher current strengths as compared withSwedish iron.

' 4t. In direct current receiver, a normally non-polarized telephone receiver core of magnetic material, having the followlng characteristics, a sharply rising flux curve on low current strengths, and a relatively fl at saturation kneeas compared with Swedish iron. I I I 5. In a direct current receiver, a normally non -polarized telephone receiver core of magnetic material having a higher permeability on low current strengths, and aloW permeability on"? high current strengths, relative to Swedish. iron. g I

6." In a direct "current receiver, a normally non-polarized telephone receiver core of magnetic material having a BH curve of sharper initial rise, and a'lower saturation point than a similar curve for Swedish iron.

7. In a telephone receiver, an electromagnet core composed otsiliconsteel. V

8. In a direct current receiver, an electromagnet comprising a laminated core of silicon steel and awinding adapted to1be energ gized by direct current V I i V v V 9. In a direct current receiver, an electromagnet comprising a plurality of sheet metal stampings of silicon steel and a winding adapted to be energized by direct current. p i

10. In a direct current receiver, an electromagnet having a core comprising a plit rality of magnetic conductors of small cross section formed of silicon steel and a diaphragm of magnetic material in operative relation to said electromagnet.

11. In combination a cup having a coni cal portion and a reduced cylindrical portion, said cylindrical portion co-extending from the reduced end of said conical portion and having a bottom portion, a magnet structure substantially filling said cylindrical portion and resting upon said bottom, said magnet structure having a winding disposed in said cup, a block of insulation Se cured to said bottom portion, a pair of terminal stampings mounted on said block and having pinsextending through said bottom portion and projecting to the said conical portion and sleeves of insulation for said pins.

12. In combination a block of insulation having a hole therethrough to adapt the same to be secured to a receiver cup, pair of terminal stampings of sheet metal secured to opposite sides of said block, said stamp ings having narrow extending pins'adapted to make connection with the terminals of a receiver winding, said pins being formed integrally with said stanipings, screws passing through said flat stampings for securing the stampings to the sides of the block and clips removably secured to said stampings for attaching and connecting the terminals of the receiver cord to said stampings.

13. In combination a prismatic block of insulation, having a hole therethrough, a

pair of flat brass stampings secured to eachside of said block, said stampings having longitudinally extending pins formed integrally therewith, said stampings being secured to said block of insulation by screws substantially flush with said stainpings, a

sleeve of insulatingmaterial for each of said longitudinally extending pins and re-,

movable terminal means secured to said stampings by individual screws for attaching and connecting the terminals of'the receiver cord to said stampings and means passing through said hole in the block for side of said block of insulation and having said bottom into said blocks for holding.

said stampings against the bottom of said cup, said blocks and stampings substantially filling he cylindrical part of said cup.

16. In combination a brass cup comprising a substantially conical portion, a cylin-r drical portion having av closed bottom joined to said conical portion,the bottom of said cup having an aperture therethrough, said aperture being countersunk upon the inside, a block of insulation, a fiat headed countersunk screw passing through. said aperture in the bottom of the cup and through said block of insulation, an L-shaped lug having threads cooperating with said screw, said lug having an eye adapted to be secured to the receiver cord.

17. In combination a prismatic block of insulation, a pair of flat terminal members secured on opposite sides of said block, said terminal members being of substantially the full width of the side to which they are at-' tached, screws lying substantially flush with the surface of the terminal members for attaching the terminal members to the block-,terminal clips having a flat'portion and a grooved portion and means for holding the terminal clips against turning with respect to said terminal members, said terminal clips being connected to and over-;

lying the terminal members.

18 In a direct current receiver,-a mag-: netic system comprising a horseshoe core and a diaphragm, said horse-shoevcore comprising laminations or silicon steel characterizedby high permeability at low current strength and low pe *meability at high current strength as compared with Swedish iron, and a winding upon. said core, saidv winding being adapted to be traversed by direct currents of relatively low current strength having variations corresponding to' voice vibrations.

19. In a direct current receiver, a magnetic system'consisting of a horse-shoe core and a diaphragm, said horse-shoe core compr1singE-shaped laminations of silicon steel,

a winding upon the central leg of said E-shaped cor said winding beingadapted to be traversed'by direct currents of relatively low current strength having variations correspondingto voice vibrations and a diaphragm adapted. to be acted upon by the magnetism of said core and being thereby-responsivein proper degree either to abnormally high, values or; abnormally low values of current strength through said winding as compared with the effective range of current strength in a receiver employing a core of Swedish iron.

20. In a telephone receiver the combinationof a core comprising laminations of silicon steel, a winding for the core, said winding being adapted to be traversed by currents corresponding to sound waves, and a diaphragm subject to the magnetic flux of said core, said core being characterized byrelatively high permeability at low current strength and relatively low permeability at. high current strength as compared with Swedish iron, whereby proper o.pera-. tion of the receiver upon abnormally weal: sound current orupon,abnormally strong sound current ispossible, and whereby better definition ofsound is secured. 7

v21. In a telephone receiver, a winding adapted to be traversed by voice currents, a

diaphraglnresponsive to, the'fluctuations of magnetism created by said voice currents, and a relatively stationary magnetic link forming the means for applying the variations of magnetism to the diaphragm to vibrate the same, said magnetic link being composed of a 1naterial ,characterized by relatively highpermeability for low values of magnetizing force applied thereto as compared with Swedish, iron, whereby the diaphragm is vibrated more vigorously for feeble voice currents and whereby speech transmissionto greater distances is.

permitted.

22. In a telephone a receiver, a 'winding adapted to be traversed by voice currents, a diaphragm responsive to the fluctuations of magnetism created by voice currents,'and

Y arelatively stationary magnetic-link form ing the means for applying the variations of magnetism to the diaphragm to vibrate the same, sald magnetlc link being composed of a material characterized by rela-.

tively high permeability for low values of magnetizing force applied thereto as com-- pared with Swed1sh lron, whereby the diaphragm is vibrated more vigorously for feeble voice currents and whereby speech transmision to greater distances is permitted, and further characterized by relatively low permeability at high values of magnetizing force applied thereto as compared with Swedish iron, whereby thediaphragm is vibrated less vigorously in proportion for voice currents of excessive strength whereby clearer definition of speech is possible for all values of the strength of the voice currents.

23. A telephone receiver core composed of magnetic material having substantially the characteristics of silicon steel.

2%. In a telephone receiver, the combination With a diaphragm, of a core having a pole arranged adjacent to said diaphragm, a Winding for the said core, said core being composed of a magnetic material having substantially the characteristics of silicon steel.

25. In a telephone receiver, the combination With a core composed of a material having substantially the characteristics of silicon steel, a magnetic Winding for the said core, and a diaphragm arranged with its midpoint adjacent to the end of said core.

In Witness whereof I hereunto subscribe my name this 6th day of May, A. D. 1916.

WILLIAM W. DEAN. 

